The mammalian cardiac atria contain a family of peptides, collectively termed atrial natriuretic peptides (ANP's), which are derived from a common precursor and possess intrinsic natriuretic, diuretic, vasorelaxant, and endocrine effects. The availability of synthetic ANP's has enabled the development of radioimmunoassays (RIA's) to localize and characterize the various extraatrial ANP's. Sound methods have been developed for the determination of plasma ANP's in order to clarify which ANP's are physiologically importance or released in vivo. Recent immunocytochemical and RIA distribution studies have localized ANP's to areas of the CNS that suggest the ANP's are involved in central cardiovascular regulatory events and in the release and/or synthesis of certain pituitary gland hormones. Additional support for the possible involvement of ANP's in regulating pituitary gland function was obtained with the demonstration that high-affinity, specific ANP binding sites are present on pituitary gland membranes. Finally, two forms of ANP are present in plasma, and their release is enhanced from the atria by activation of atrial-stretch receptors, as well as adrenergic, cholinergic, and vasopressinergic agonists. We are currently evaluating the effect of ethanol on the ANP system in animals and the possible involvement of ANP's in certain cardiovascular pathologies associated with alcohol-related disorders in patients.
